Unit 2 Biology - Stem cells

Cord blood

Cord blood is a sample of blood taken from a newborn baby's umbilical cord. It is a rich source of hematopoietic stem cells, which are precursors to blood cells. As such, they have been used to treat certain diseases of the blood and immune system.

Ectoderm

Ectoderm is one of the three primary germ layers in the very early embryo. The ectoderm as the most exterior (or distal) layer. It emerges and originates from the outer layer of germ cells.

Embryonic stem cells

Embryonic stem cells (ES cells) are pluripotent stem cells derived from the inner cell mass of a blastocyst, an early-stage preimplantation embryo. Human embryos reach the blastocyst stage 4-5 days post fertilisation, at which time they consist of 50-150 cells.

Hematopoietic stem cells

Hematopoietic stem cells (HSCs) are multipotent, self-renewing progenitor cells that develop from mesodermal hemangioblast cells. All differentiated blood cells from the lymphoid and myeloid lineages arise from HSCs. HSCs can be found in adult bone marrow, peripheral blood, and umbilical cord blood.

Potency

In biology, oligopotency is the ability of progenitor cells to differentiate into a few cell types. It is a degree of potency. Examples of oligopotent stem cells are the lymphoid or myeloid stem cells.

Foetus

In human development, a fetus or foetus (/ˈfiːtəs/; plural fetuses or foetuses) is a prenatal human between its embryonic state and its birth. The fetal stage of development tends to be taken as beginning at the gestational age of eleven weeks, i.e. nine weeks after fertilisation.

Gastrula

Split into three germ layers are known as the ectoderm, mesoderm, and endoderm.

Stem cell therapy

Stem-cell therapy is the use of stem cells to treat or prevent a disease or condition. Bone marrow transplant is the most widely used stem-cell therapy, but some therapies derived from umbilical cord blood are also in use.

Totipotent

The ability of totipotent stem cells to differentiate into any cell in an organism including embryonic tissue is an important distinguishing quality. A human totipotent stem cell can thus develop into any cell in the body, including placental cells

Germ layers

The germ layers develop early in embryonic life, through the process of gastrulation. During gastrulation, a hollow cluster of cells called a blastula reorganises into two primary germ layers: an inner layer, called endoderm, and an outer layer, called ectoderm.

Morula

a solid ball of cells resulting from division of a fertilised ovum, and from which a blastula is formed.

Endoderm

the innermost layer of cells or tissue of an embryo in early development, or the parts derived from this, which include the lining of the gut and associated structures.

Mesoderm

the middle layer of cells or tissues of an embryo, or the parts derived from this (e.g. cartilage, muscles, and bone)

Unipotent

Found in adult tissues, a unipotent stem cell, in comparison with other types of stem cells, has the lowest differentiation potential.

Gastrulation

Gastrulation is a phase early in the embryonic development of most animals, during which the single-layered blastula is reorganised into a trilaminar ("three-layered") structure known as the gastrula.

Multipotent

Multipotent cells can develop into more than one cell type, but are more limited than pluripotent cells; adult stem cells and cord blood stem cells are considered multipotent.

Blastocyst

a mammalian blastula in which some differentiation of cells has occurred.

Embryo

an unborn or unhatched offspring in the process of development.

Pluripotent

(of an immature cell or stem cell) capable of giving rise to several different cell types. "many types of cells originate from pluripotent bone marrow stem cells"

Adult stem cells

Adult stem cells are undifferentiated cells, found throughout the body after development, that multiply by cell division to replenish dying cells and regenerate damaged tissues